Abstract: In recent years the field of virtual reality has witnessed a rapid growth with significant investments in both hardware and software development. It has several potential applications for entertainment, education and enterprise where users benefit from being immersed into virtual worlds. VR headsets are available in several forms and price ranges from simple and inexpensive Google Cardboard to more complex products such as Oculus Rift. Nevertheless, designing fully operational virtual reality applications for researching new complex multimodal interaction possibilities (e.g. mid-air gesture, voice, haptics, etc.) may be difficult to implement, costly and time consuming. For this reason we have looked into ways of rapidly prototyping virtual reality interactions. Our approach consists of the Wizard of Oz experiment in which subjects interact with a computer system believing to be autonomous, but is in reality operated by researchers. The presented system allows non-technical designers to explore various multimodal interactions with rapid prototyping of VR environments.